Hi:
My 1994 Mercedes E320 wagon smells like burning oil after driving and I noticed blue smoke coming back of the engine near the firewall. I checked for oil leaks under the vehicle and cannot find the the location of the oil leak and/or source of the blue smoke . Then I did some research on this issue and from what others are saying is that the head gasket is worn out and needs to be replace. Is that true and does anybody has this issue? Comments and/or feedback is greatly appreciated.

Likely the head gasket, but I'll let other members throw in their 2 cents. In case it is the head gasket, I've attached a DIY tech article on replacing it. I hope it helps you out and best of luck!

Head Gasket Replacement



-Dmitry

Hi Dimitry. Thank you for your above message and advice including the DIY head gasket replacements link. I appreciated it. I am still waiting for other members for their 2 cents worth on this issue before I go ahead and do this job.

Those two things have duck analogies: quacks like a duck & walks like a duck.
In the duck case, it probably is a duck.
In this case, the smell of burning oil & the blue (oil) smoke, indicate that there probably is an oil leak.

Step #1: find the source of the smell and the smoke. If burning oil, is it burning on an exhaust manifold, or on a down pipe.
Step #2: find the source of the oil leak.
Step #3: decide what part(s) need to be changed/repaired to eliminate the leak.

Don't underestimate the possibility of a valve cover gasket being hard or leaking. The leak would be in the same area as the head gasket, but higher up.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Frank and Diseasel300. Thanks for your imputs on this issue. I appreciated it. It looks like a lot of areas to find the source of the oil leak and the blue smoke. I will keep you guys posted.

X2 on checking the valve cover gasket first. Thought my 104 leak was the head gasket..., it was the valve cover gasket. THAT went in the win column!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

I just order valve cover gasket as a first step. Stay tuned.

Don't forget the round rubber seals that go around the valve cover bolts, usually not in the valve cover kit IIRC. Not to be confused with the seals that go around the spark plug holes which are pictured and included in the kit.

Good luck!!!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Sugar Bear, Here is the image of the valve cover gasket I ordered. In the picture, you will see 6 rubber round seals. I am not sure about the other 2 that looks like some kind of bent rubber.What are these 2 rubber bent part name and where does these 2 go to? This is my first time to do this valve cover gasket replacement job. The valve cover gasket kit will arrive on Monday, January 30.

Attached Thumbnails

 

The valve cover grommet/bolt seals are on this page, quantity needed 12:
1993 Mercedes-Benz 300E Base Sedan - Cylinder Head & Valvetrain - Page 1

This is an easy valve cover gasket to replace. Use an inch pound torque wrench for tightening and do not over torque the bolts. The bolts that hold the coil/spark plug cover in place are often already stripped.

In the diagram the large gasket around the perimeter is the valve cover gasket. The six round seals in the center are spark plug access hole seals and the two half moon seals go at the back of the valve cover. You will understand it when you have the cover off and see it.

Some will disagree; but, I would put a small, sparing amount of black RTV around the half moon seal edges.

This car is from the era of engine wiring harness problems. If you do not know if the harness has been replaced try to find out first by inspecting it for cracked insulation. If it has not been replaced and is cracked you may wish to hold off on doing the valve cover gasket until it is confirmed that the valve cover is leaking. if the cover is not leaking and the harness is disturbed to change a non-leaking gasket a problem will be created instead of solved.

If you need a harness send me a PM, hopefully you do not and yours has already been replaced...many have.

Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

All the above are repair suggestions, but you don't know what is wrong. First step should be a thorough cleaning of the engine so you can pinpoint the location of the oil leak.

I got the valve cover gasket kit today. I just remember something about torque specifications. I can't seem to find anywhere on this forum in regards to this issue. Maybe I am using the wrong search terms. Is there a list of some kind somewhere that tells what are torque specifications on my 1994 Mercedes E320 wagon?

Sugar Bear, Thank you for reminding me of the replacement of 12 gommets for the valve cover. I ordered the 12 gommets today. When I removed the 12 bolts on the valve cover to put in a new replacement valve cover gasket, I noticed three of the metal sleeves in which the bolts goes inside have missing rubber/metal washers or gommets.The rubber/metal washer together/combined is in one piece. Those rubber/metal washers goes on the outside of the bolt sleeves, not outside the bolts. In addition, inside the 6 spark plugs holes, oil is everywhere (spark plugs remained intact and had not removed). The old valve cover gasket and the six seals looks worn and torn. The three coils are fine, just dirty with oil. Spark plug wires are in good shape and, again, dirty with oil. Will clean up the coils, valve cover, and spark plug wires. In addition, I will replace with new spark plugs due to oil around the old spark plugs, just to play it safe as well as clean up the inside the spark plug holes once removing the spark plugs prior to replacing with new spark plugs. Thanks to all who have been reading and posting on this issue.

dmorgan, no need to replace the spark plugs unless they are due for replacement ... every 30,000 miles. Sop up/vacuum the oil around the spark plugs and use some cleaner on a rag to clean the area and the spark plugs thoroughly. Check inside the ignition wires for oil, and clean as required. Apparently routine maintenance of this engine has been ignored for quite a while.

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Fred Hoelzle